Hammerling

Griffith

Frederick, 1928; discovered a transforming factor by chance while looking at pneumonia vaccines; he injected mice with good and bad strands of the virus, discovering that something from the bad strand was able to leak out even when it had been denatured, and still affect the mouse.

Avery

Viruses

Hershey and Chase

Alfred and Martha, 1952; test to see if viruses carry genetic info on DNA or protein; tagged both protein and DNA with different radioactive atoms to see which one carried on inside the cell; DNA was carried on